Run RFM v4.3 to replicate RFM v4.2 (specifically
Use polynomial expressions for Partition Sum calculations for
Temperature dependence of HITRAN line strengths
Extrapolate temperature dependence of cross-section data
using (296/T)3/2 or molecule-specific rule
Use 4th order Lagrangian interpolation for Partition Sums
No temperature dependence of cross-section data beyond tabulated range.
The new Lagrangian interpolation is more accurate since it interpolates
data from tabulated values at 25K increments
(module qtfct.for), whereas the old polynomial
expression covered the range 70-500K with a single cubic fit
The original RFM modifications for the temperature-dependence of
tabulated cross-section data (module qtint.for)
were inherited from GENLN2 (c1990s) and, while
the 3/2 power rule might be reasonable for the central Q-branches it is
the wrong sign for the wings.
In any case cross-section data nowadays usually comes tabulated at a
range of temperatures so extrapolation is generally not required.